What was found
LAV 3L SINK OVERFLOWED WITH BROWN WATER ON CLIMBOUT CREW DEBRIEFED. STATED 3L LAV SINK LEAKED AT 22000FT BEFORE STOPPING AND WAS "GARGLING". ON MAINT ARRIVAL ALL SINKS EMPTY AND FOUND SMALL WET PATCH ON CARPET AFT OF DOOR 3 LAV BULKHEAD AIR MODE SIMULATION PEEFORMED REF AMM 32-09-00-860-801. DRAIN MAST AND GRAY WATER DRAIN LINE HEATERS OPERATIONAL TEST PERFORMED REF AMM 30-71-00-720-801 FWD DRAIN MAST HEATS AS NORMAL WHEN IN AIR SIMULATION AND WATER FLOWS FREELY FROM ALL LAVS AND GALLEYS ASSOCIATED WITH FWD DRAIN MAST DRAIN MAST RESTRICTOR VALVE OPS TEST PERFORMED REF AMM 38-31-00-700-801. DRAIN MAST RESTRICTOR VALVE CYCLES TO OPEN, THEN TO CLOSED AS REQUIRED WHEN DRAIN MAST PLUG IS INSTALLED/REMOVED AIRCRAFT RESTORED TO GROUND MODE REF AMM 32-09-00-440-801 REFER LP 8619170 FOR ASSICIATED MEL ACTIONS . LAV 3F-LC SINK FOUND WITH CRACK UNDER BASIN. MEL 3810AL COMPLIED WITH ,WATER HEATERS TURNED OFF ,WATER SYSTEM ISOLATED AT AFFECTED LAVATORIES,DOORS LOCKED AND SECURED. MEL 3810AL COMPLIED WITH. REVERSED MEL. LAV 3F-LC SINK FOUND DRAIN VALVE ASSY LOOSENED AND NOT CRACKED. TIGHTENED AND APPLIED NEW SEALANT REF CMM 25-46-34. OPS CHECK GOOD. LEAK CHECK GOOD.